A Chicago police officer pleaded guilty Friday to stealing $5,200 in cash that he thought belonged to a drug dealer. But the money was really part of an undercover sting.

Wentworth District tactical unit Officer Kallatt Mohammed also admitted in his plea deal, entered in federal court Friday morning, that he took protection money from heroin and crack dealers at the Ida B. Wells public housing complex on the South Side in 2007 and 2008.

[...]According to a federal criminal complaint, Mohammed, 47, a 14-year veteran of the department, took a bag containing the cash and a court-authorized tracking device from a homeless man who was working as an informant for the FBI.